/r/Biochemistry

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/r/Biochemistry

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5

Question about ammonia detoxification

If we say:

Alpha Keto Glutarate ----> Glutamate (Glutamate Dehydrogenase) ----> less TCA

Glutamate to Glutamine (Glutamine synthatase) --> less neurotransmitters

Are the reasons NH3 is toxic

How does the Glutamate Dehydrogenase reaction detoxify NH3,

and how does synthesis of glutamine detoxify NH3 (I think this is because Glutamine is transfered to tissues where glutaminase is present and is converted back to glutamate, is this true?? ----> but then doesnt this release ammonia again)

7 Comments
2023/06/05
16:58 UTC

1

Root border cells

0 Comments
2023/06/05
16:04 UTC

0

Graduating College

I'm graduating college very soon and began applying to places. I'd like to travel and land a remote job for the next year but would like to work in something still pertinent to my major to build experience. What sort of jobs would you all apply to?

2 Comments
2023/06/05
16:02 UTC

4

Chaotropic buffer precipitation

I observe some strange behaviour of my DNA binding buffer. It falls out after 2 or 3 days in the fridge and it is also difficult to mix.

The formula:

  • 4 M Guanidinium hydrochloride
  • 10 mM Tris
  • 4 mM EDTA Na2

all in 90% isopropanol

pH (water phase) native ~ 8 then adjusted with HCl to ~ 5,5

Firstly: I can't simply add the 3 ingredients at the same time as they simply won't go into solution, no matter how long I stir as soon as I add the IPA. If I however dissolve EDTA and Tris first (adjust pH there) and add GHCl later it goes into solution easily. Why?

Now if I leave my buffer in the fridge over the weekend I get some precipitation (small granular) which never goes into solution again.

What is happening here???

I suspect a complex formation between EDTA and GHCl although it does not seem sterically favourable. Any other suggestions??

1 Comment
2023/06/05
13:18 UTC

2

Using DHE to measure H202 in yeast, and some general yeast plate assay questions

Hi biochemists,

DHE undergoes oxidation by ROS (like H202) to form ethidium (ex 480 nm/em 576 nm). Using FACS, we can clearly see an intensity shift of DHE-stained yeast at this wavelength under oxidative conditions.

How could I adapt this to a plate assay so I can estimate [H202] in yeast nuclei?

My concern is that yeast would need to be present (because the ethidium needs to bind DNA to fluoresce), however, the cells will all settle to the bottom of the plate and affect my reading. Another concern is the auto-fluorescence of yeast causing too much background.

Has anyone done plate assays with yeast fluorescence that could provide some tips?

1 Comment
2023/06/04
21:15 UTC

3

Would you mind checking my understanding of affinity chromatography vs ion exchange chromatography please?

Both are column chromatography, where you have stationary resin and you pour the solution down the column to see which sticks to the resin.

Affinity chromatography is attaching a TAG (eg histidine tag via attaching an imidazole group) to the compound of interest so that the tag will attach to the beads in the column while other compounds elute out. You can elute the compound of interest by using an excess of analogs to the tag you used

Ion exchange chromatography uses CHARGES to separate compounds from the solution. You elute it with an excess of the same charge as the one found on your compounds of interest

1 Comment
2023/06/04
15:44 UTC

2

Doing grad exam test prep and confused about why spectrophotometry can't detect the difference between an individual histidine vs histidine dipeptide?

https://imgur.com/a/lX2UZ8N

Could you also explain why B is right? I thought B is wrong because histidine is polar and dihistidine would also be polar so they'll both stick to the stationary phase of the HPLC

2 Comments
2023/06/04
15:16 UTC

111

Damn you ever wish you were a phospholipid in a cellular membrane, membrane receptors look like they know how to throw a phospholipid party

9 Comments
2023/06/04
12:47 UTC

2

histidine which confers a charge as a conjugate acid and has a pKa of 6 is in a pH of 8.5, would it just confer zero charge ? Because wouldn’t it be in a basic state at that point ?

14 Comments
2023/06/04
03:50 UTC

0

Currently in Biochem (Chem 210) at Portage Learning.

0 Comments
2023/06/04
03:35 UTC

6

Issue with coot and rotamers

Hi everyone, I am new to coot and am trying to fit my model into my experimental density. However, when I try to see which rotamer would fit best, I get a list of different rotamers, and when I click on them nothing happens. Does anyone know what the problem is and how to fix it?

5 Comments
2023/06/04
03:08 UTC

3

German cancer research center

Hello everyone, I would really appreciate some feedback about DKFZ, and will they accept me to do my master thesis there. also, some bullet points about motivation letter and the CV , besides which documents should I send with the application as there are no criteria for it. Btw I am a master's student in Germany, major biochemistry Thanks in advance :)

1 Comment
2023/06/04
00:11 UTC

2

How does Aminoacyl-tRNA Synthetases associate a tRNA with the respective codon?

Hello! I had a question about how aminoacyl-tRNA synthetases are able to associate the correct tRNA with the corresponding codon during the tRNA charging process of translation. I'm unsure of what actually goes on mechanistically speaking - does it involve the proofreading site of the synthetase? Are there other protein factors involved?

Also as a side question, what is the difference between a synthetase and a synthase, if there is any?

Thanks to everyone who answers!

5 Comments
2023/06/03
23:43 UTC

16

Confused about NADPH in the Pentose Phosphate Pathway

My understanding is (relating to Red Blood Cells):

NADPH is used to form superoxides, superoxides form H2O2 which is bad because it leads to hemolysis

If it's bad, Why does impairment of NADPH Production ( Glucose-6-phosphate dehydrogenase deficiency) lead to H2O2 detoxification being inhibited ----> if there's less NADPH, doesn't this mean Less Super oxides?? Less Hemolysis??

Please correct me or clear up my confusion if possible

8 Comments
2023/06/03
19:28 UTC

7

Is acetone used a ketone body for energy or it is just excreted?

I know that we get acetone from acetoacetate by decarboxylation, which is then excreted through urine and respiration. But is the reaction reversible so that we could use it to synthesize acetyl-CoA to generate energy?

9 Comments
2023/06/03
10:36 UTC

0

Please HELPp quickly

What is the difference between deoxyribonucleoside triphosphate and deoxyribonucleotide triphosphate

2 Comments
2023/06/03
04:48 UTC

1

Any good biochemistry textbooks?

Hi! I'm a high schooler and I'm going into research for lipid metabolism this July

I wanted to study up on some biochemistry (beyond the monosaccharides are carbonhydrates teehee stuff you find in AP textbooks)

Is there anything good I can study off of?

Thanks so much :DDDDD

11 Comments
2023/06/03
01:45 UTC

15

Does oxidative phosphorylation always imply that oxygen is the final electron acceptor?

9 Comments
2023/06/02
23:47 UTC

1

What would happen if you inject a YAP activator in an organ

would it change morphology?

2 Comments
2023/06/02
21:05 UTC

6

Bad grades freshman year need advice

I just finished my first year as a biochem and molecular biology undergrad at umass but i finished with around a 2.65 gpa. I got a lot of Cs, especially this semester so how did you guys develop good study skills and focus in classes you didnt like? I hated bio and my gen eds and really struggled to focus and had trouble remembering to do all my assignments (although I did most of them), and orgo 1 was hard since my usual study methods werent working. What do i do?

3 Comments
2023/06/02
20:18 UTC

12

Kd = Kon/Koff? Or is this a different Kd?

According to Time, the forgotten dimension of ligand binding teaching, Kd = Kon/Koff :

Kd is the equilibrium constant for the dissociation equilibrium, it is equal to Kon/Koff, and its units are M. It should not be confused with Koff, which is the rate constant for the breaking of the complex. Kd is the parameter of the association equilibrium that is generally discussed and tabulated in textbooks. It is inversely related to the affinity of the protein for the ligand, and the fact that when ligand concentration equals Kd, the protein is 50% saturated is stated in most biochemistry textbooks.

I normally refer to Kd as the dissociation constant equal to Koff/Kon. Is the author talking about a different constant? This paper has dozens of citations and no corrections, so I’m doubting myself.

7 Comments
2023/06/02
16:28 UTC

0

Who says life can’t be carbon based?

I designed this complex life molecule cell. The perchlorate and peroxide bonds are a source of energy in the cells, and iron and iridium can be high-valent and make complexes for complex life molecules. The sulfur chain is the cell wall to protect it from fl*orine.

https://preview.redd.it/hlfjeca19m3b1.jpg?width=1412&format=pjpg&auto=webp&v=enabled&s=cc76a90c5e51484fafa83f4caaa81b15c9f6c717

1 Comment
2023/06/02
14:37 UTC

0

Homocysteine back high quickly

After taking vitamin b supplements, due to my high Homocysteine of 12 my homocysteine levels decreased to 8.

A month has passed, and after another blood test yesterday, my homocysteine is back to 11

Does anyone know why it jumps back up so quickly and how to lower homocysteine so it stays low ?

1 Comment
2023/06/02
13:40 UTC

14

New r/ChemThermo or “chemical thermodynamics” sub launched if interested?

1 Comment
2023/06/02
05:29 UTC

13

Noradrenaline discrimination between alpha and beta adrenoreceptors

I'm a first year Biochem student so my knowledge isn't quite all that amazing at the moment.

Just revising for exams and came across how NA binds to alpha1+2 adrenoreceptors to cause vasoconstriction but beta2 to cause vasodilation - what stops NA from binding to beta receptors when vasoconstriction is required via the alpha receptors? (or vice versa)

This may be a dumb question but I couldn't find an answer on google (as I find happens for most of my super specific questions I have like this!)

4 Comments
2023/06/01
16:08 UTC

2

How to draw free-energy diagram (reaction coordinate) for publication?

Anyone have a way to draw a free-energy diagram to show a reaction coordinate for publication?

Thanks!

1 Comment
2023/06/01
16:07 UTC

7

Microbiome-dependent gut–brain pathway regulates motivation of exercise: A Nature study found that microbiome-derived metabolites in the gut can stimulate sensory neurons to elevate dopamine levels in the brain, and therefore induce exercise motivation in mice.

0 Comments
2023/06/01
04:12 UTC

1

Redox Cofactors and Oxidative Stress - ETC, haem synthesis, porphyria, vitamin E/B2/B3 [01:02:39]

0 Comments
2023/06/01
01:32 UTC

0

Should I get an iPad?

I've been hearing a lot of good stuff about iPads for note taking and etc instead of using notebooks and I have been considering it but I want to hear some pros and cons of it. I really like using notebooks because I am kinda old school and I think I learn better taking hand written notes. anything advice or tips will help hehe

7 Comments
2023/05/31
20:58 UTC

11

Linkage groups for attachment of organic molecules to amino/proteins

Hi guys,

Forgive me if this is a stupid question, I'm a chemist not a biochemist. I'm currently doing undergrad research and I'm looking for a list of functional groups that are commonly used to link molecules to amino acids / proteins. To expand upon this, I have an organic molecule and I want to exhaust all of my possibilities as to how I could attach this organic molecule to an antibody. My starting material is going to be a brominated aromatic molecule so ideally I am looking to do a nucleophilic substitution on this bromo that will leave the aromatic molecule with the functional group of choice now making it possible to attach my molecule to an antibody.

I'm not sure which functional groups work best for my purpose but from what I know thiocyanates and alpha beta unsaturated ketones are very good. Any good sources where I could learn more about this?

16 Comments
2023/05/31
20:12 UTC

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